1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * ALSA sequencer Priority Queue |
4 | * Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl> |
5 | */ |
6 | |
7 | #include <linux/time.h> |
8 | #include <linux/slab.h> |
9 | #include <sound/core.h> |
10 | #include "seq_timer.h" |
11 | #include "seq_prioq.h" |
12 | |
13 | |
14 | /* Implementation is a simple linked list for now... |
15 | |
16 | This priority queue orders the events on timestamp. For events with an |
17 | equeal timestamp the queue behaves as a FIFO. |
18 | |
19 | * |
20 | * +-------+ |
21 | * Head --> | first | |
22 | * +-------+ |
23 | * |next |
24 | * +-----v-+ |
25 | * | | |
26 | * +-------+ |
27 | * | |
28 | * +-----v-+ |
29 | * | | |
30 | * +-------+ |
31 | * | |
32 | * +-----v-+ |
33 | * Tail --> | last | |
34 | * +-------+ |
35 | * |
36 | |
37 | */ |
38 | |
39 | |
40 | |
41 | /* create new prioq (constructor) */ |
42 | struct snd_seq_prioq *snd_seq_prioq_new(void) |
43 | { |
44 | struct snd_seq_prioq *f; |
45 | |
46 | f = kzalloc(size: sizeof(*f), GFP_KERNEL); |
47 | if (!f) |
48 | return NULL; |
49 | |
50 | spin_lock_init(&f->lock); |
51 | f->head = NULL; |
52 | f->tail = NULL; |
53 | f->cells = 0; |
54 | |
55 | return f; |
56 | } |
57 | |
58 | /* delete prioq (destructor) */ |
59 | void snd_seq_prioq_delete(struct snd_seq_prioq **fifo) |
60 | { |
61 | struct snd_seq_prioq *f = *fifo; |
62 | *fifo = NULL; |
63 | |
64 | if (f == NULL) { |
65 | pr_debug("ALSA: seq: snd_seq_prioq_delete() called with NULL prioq\n" ); |
66 | return; |
67 | } |
68 | |
69 | /* release resources...*/ |
70 | /*....................*/ |
71 | |
72 | if (f->cells > 0) { |
73 | /* drain prioQ */ |
74 | while (f->cells > 0) |
75 | snd_seq_cell_free(cell: snd_seq_prioq_cell_out(f, NULL)); |
76 | } |
77 | |
78 | kfree(objp: f); |
79 | } |
80 | |
81 | |
82 | |
83 | |
84 | /* compare timestamp between events */ |
85 | /* return 1 if a >= b; 0 */ |
86 | static inline int compare_timestamp(struct snd_seq_event *a, |
87 | struct snd_seq_event *b) |
88 | { |
89 | if ((a->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK) { |
90 | /* compare ticks */ |
91 | return (snd_seq_compare_tick_time(a: &a->time.tick, b: &b->time.tick)); |
92 | } else { |
93 | /* compare real time */ |
94 | return (snd_seq_compare_real_time(a: &a->time.time, b: &b->time.time)); |
95 | } |
96 | } |
97 | |
98 | /* compare timestamp between events */ |
99 | /* return negative if a < b; |
100 | * zero if a = b; |
101 | * positive if a > b; |
102 | */ |
103 | static inline int compare_timestamp_rel(struct snd_seq_event *a, |
104 | struct snd_seq_event *b) |
105 | { |
106 | if ((a->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK) { |
107 | /* compare ticks */ |
108 | if (a->time.tick > b->time.tick) |
109 | return 1; |
110 | else if (a->time.tick == b->time.tick) |
111 | return 0; |
112 | else |
113 | return -1; |
114 | } else { |
115 | /* compare real time */ |
116 | if (a->time.time.tv_sec > b->time.time.tv_sec) |
117 | return 1; |
118 | else if (a->time.time.tv_sec == b->time.time.tv_sec) { |
119 | if (a->time.time.tv_nsec > b->time.time.tv_nsec) |
120 | return 1; |
121 | else if (a->time.time.tv_nsec == b->time.time.tv_nsec) |
122 | return 0; |
123 | else |
124 | return -1; |
125 | } else |
126 | return -1; |
127 | } |
128 | } |
129 | |
130 | /* enqueue cell to prioq */ |
131 | int snd_seq_prioq_cell_in(struct snd_seq_prioq * f, |
132 | struct snd_seq_event_cell * cell) |
133 | { |
134 | struct snd_seq_event_cell *cur, *prev; |
135 | int count; |
136 | int prior; |
137 | |
138 | if (snd_BUG_ON(!f || !cell)) |
139 | return -EINVAL; |
140 | |
141 | /* check flags */ |
142 | prior = (cell->event.flags & SNDRV_SEQ_PRIORITY_MASK); |
143 | |
144 | guard(spinlock_irqsave)(l: &f->lock); |
145 | |
146 | /* check if this element needs to inserted at the end (ie. ordered |
147 | data is inserted) This will be very likeley if a sequencer |
148 | application or midi file player is feeding us (sequential) data */ |
149 | if (f->tail && !prior) { |
150 | if (compare_timestamp(a: &cell->event, b: &f->tail->event)) { |
151 | /* add new cell to tail of the fifo */ |
152 | f->tail->next = cell; |
153 | f->tail = cell; |
154 | cell->next = NULL; |
155 | f->cells++; |
156 | return 0; |
157 | } |
158 | } |
159 | /* traverse list of elements to find the place where the new cell is |
160 | to be inserted... Note that this is a order n process ! */ |
161 | |
162 | prev = NULL; /* previous cell */ |
163 | cur = f->head; /* cursor */ |
164 | |
165 | count = 10000; /* FIXME: enough big, isn't it? */ |
166 | while (cur != NULL) { |
167 | /* compare timestamps */ |
168 | int rel = compare_timestamp_rel(a: &cell->event, b: &cur->event); |
169 | if (rel < 0) |
170 | /* new cell has earlier schedule time, */ |
171 | break; |
172 | else if (rel == 0 && prior) |
173 | /* equal schedule time and prior to others */ |
174 | break; |
175 | /* new cell has equal or larger schedule time, */ |
176 | /* move cursor to next cell */ |
177 | prev = cur; |
178 | cur = cur->next; |
179 | if (! --count) { |
180 | pr_err("ALSA: seq: cannot find a pointer.. infinite loop?\n" ); |
181 | return -EINVAL; |
182 | } |
183 | } |
184 | |
185 | /* insert it before cursor */ |
186 | if (prev != NULL) |
187 | prev->next = cell; |
188 | cell->next = cur; |
189 | |
190 | if (f->head == cur) /* this is the first cell, set head to it */ |
191 | f->head = cell; |
192 | if (cur == NULL) /* reached end of the list */ |
193 | f->tail = cell; |
194 | f->cells++; |
195 | return 0; |
196 | } |
197 | |
198 | /* return 1 if the current time >= event timestamp */ |
199 | static int event_is_ready(struct snd_seq_event *ev, void *current_time) |
200 | { |
201 | if ((ev->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK) |
202 | return snd_seq_compare_tick_time(a: current_time, b: &ev->time.tick); |
203 | else |
204 | return snd_seq_compare_real_time(a: current_time, b: &ev->time.time); |
205 | } |
206 | |
207 | /* dequeue cell from prioq */ |
208 | struct snd_seq_event_cell *snd_seq_prioq_cell_out(struct snd_seq_prioq *f, |
209 | void *current_time) |
210 | { |
211 | struct snd_seq_event_cell *cell; |
212 | |
213 | if (f == NULL) { |
214 | pr_debug("ALSA: seq: snd_seq_prioq_cell_in() called with NULL prioq\n" ); |
215 | return NULL; |
216 | } |
217 | |
218 | guard(spinlock_irqsave)(l: &f->lock); |
219 | cell = f->head; |
220 | if (cell && current_time && !event_is_ready(ev: &cell->event, current_time)) |
221 | cell = NULL; |
222 | if (cell) { |
223 | f->head = cell->next; |
224 | |
225 | /* reset tail if this was the last element */ |
226 | if (f->tail == cell) |
227 | f->tail = NULL; |
228 | |
229 | cell->next = NULL; |
230 | f->cells--; |
231 | } |
232 | |
233 | return cell; |
234 | } |
235 | |
236 | /* return number of events available in prioq */ |
237 | int snd_seq_prioq_avail(struct snd_seq_prioq * f) |
238 | { |
239 | if (f == NULL) { |
240 | pr_debug("ALSA: seq: snd_seq_prioq_cell_in() called with NULL prioq\n" ); |
241 | return 0; |
242 | } |
243 | return f->cells; |
244 | } |
245 | |
246 | /* remove cells matching with the condition */ |
247 | static void prioq_remove_cells(struct snd_seq_prioq *f, |
248 | bool (*match)(struct snd_seq_event_cell *cell, |
249 | void *arg), |
250 | void *arg) |
251 | { |
252 | register struct snd_seq_event_cell *cell, *next; |
253 | struct snd_seq_event_cell *prev = NULL; |
254 | struct snd_seq_event_cell *freefirst = NULL, *freeprev = NULL, *freenext; |
255 | |
256 | /* collect all removed cells */ |
257 | scoped_guard(spinlock_irqsave, &f->lock) { |
258 | for (cell = f->head; cell; cell = next) { |
259 | next = cell->next; |
260 | if (!match(cell, arg)) { |
261 | prev = cell; |
262 | continue; |
263 | } |
264 | |
265 | /* remove cell from prioq */ |
266 | if (cell == f->head) |
267 | f->head = cell->next; |
268 | else |
269 | prev->next = cell->next; |
270 | if (cell == f->tail) |
271 | f->tail = cell->next; |
272 | f->cells--; |
273 | |
274 | /* add cell to free list */ |
275 | cell->next = NULL; |
276 | if (freefirst == NULL) |
277 | freefirst = cell; |
278 | else |
279 | freeprev->next = cell; |
280 | freeprev = cell; |
281 | } |
282 | } |
283 | |
284 | /* remove selected cells */ |
285 | while (freefirst) { |
286 | freenext = freefirst->next; |
287 | snd_seq_cell_free(cell: freefirst); |
288 | freefirst = freenext; |
289 | } |
290 | } |
291 | |
292 | struct prioq_match_arg { |
293 | int client; |
294 | int timestamp; |
295 | }; |
296 | |
297 | static inline bool prioq_match(struct snd_seq_event_cell *cell, void *arg) |
298 | { |
299 | struct prioq_match_arg *v = arg; |
300 | |
301 | if (cell->event.source.client == v->client || |
302 | cell->event.dest.client == v->client) |
303 | return true; |
304 | if (!v->timestamp) |
305 | return false; |
306 | switch (cell->event.flags & SNDRV_SEQ_TIME_STAMP_MASK) { |
307 | case SNDRV_SEQ_TIME_STAMP_TICK: |
308 | if (cell->event.time.tick) |
309 | return true; |
310 | break; |
311 | case SNDRV_SEQ_TIME_STAMP_REAL: |
312 | if (cell->event.time.time.tv_sec || |
313 | cell->event.time.time.tv_nsec) |
314 | return true; |
315 | break; |
316 | } |
317 | return false; |
318 | } |
319 | |
320 | /* remove cells for left client */ |
321 | void snd_seq_prioq_leave(struct snd_seq_prioq *f, int client, int timestamp) |
322 | { |
323 | struct prioq_match_arg arg = { client, timestamp }; |
324 | |
325 | return prioq_remove_cells(f, match: prioq_match, arg: &arg); |
326 | } |
327 | |
328 | struct prioq_remove_match_arg { |
329 | int client; |
330 | struct snd_seq_remove_events *info; |
331 | }; |
332 | |
333 | static bool prioq_remove_match(struct snd_seq_event_cell *cell, void *arg) |
334 | { |
335 | struct prioq_remove_match_arg *v = arg; |
336 | struct snd_seq_event *ev = &cell->event; |
337 | struct snd_seq_remove_events *info = v->info; |
338 | int res; |
339 | |
340 | if (ev->source.client != v->client) |
341 | return false; |
342 | |
343 | if (info->remove_mode & SNDRV_SEQ_REMOVE_DEST) { |
344 | if (ev->dest.client != info->dest.client || |
345 | ev->dest.port != info->dest.port) |
346 | return false; |
347 | } |
348 | if (info->remove_mode & SNDRV_SEQ_REMOVE_DEST_CHANNEL) { |
349 | if (! snd_seq_ev_is_channel_type(ev)) |
350 | return false; |
351 | /* data.note.channel and data.control.channel are identical */ |
352 | if (ev->data.note.channel != info->channel) |
353 | return false; |
354 | } |
355 | if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_AFTER) { |
356 | if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_TICK) |
357 | res = snd_seq_compare_tick_time(a: &ev->time.tick, b: &info->time.tick); |
358 | else |
359 | res = snd_seq_compare_real_time(a: &ev->time.time, b: &info->time.time); |
360 | if (!res) |
361 | return false; |
362 | } |
363 | if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_BEFORE) { |
364 | if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_TICK) |
365 | res = snd_seq_compare_tick_time(a: &ev->time.tick, b: &info->time.tick); |
366 | else |
367 | res = snd_seq_compare_real_time(a: &ev->time.time, b: &info->time.time); |
368 | if (res) |
369 | return false; |
370 | } |
371 | if (info->remove_mode & SNDRV_SEQ_REMOVE_EVENT_TYPE) { |
372 | if (ev->type != info->type) |
373 | return false; |
374 | } |
375 | if (info->remove_mode & SNDRV_SEQ_REMOVE_IGNORE_OFF) { |
376 | /* Do not remove off events */ |
377 | switch (ev->type) { |
378 | case SNDRV_SEQ_EVENT_NOTEOFF: |
379 | /* case SNDRV_SEQ_EVENT_SAMPLE_STOP: */ |
380 | return false; |
381 | default: |
382 | break; |
383 | } |
384 | } |
385 | if (info->remove_mode & SNDRV_SEQ_REMOVE_TAG_MATCH) { |
386 | if (info->tag != ev->tag) |
387 | return false; |
388 | } |
389 | |
390 | return true; |
391 | } |
392 | |
393 | /* remove cells matching remove criteria */ |
394 | void snd_seq_prioq_remove_events(struct snd_seq_prioq * f, int client, |
395 | struct snd_seq_remove_events *info) |
396 | { |
397 | struct prioq_remove_match_arg arg = { client, info }; |
398 | |
399 | return prioq_remove_cells(f, match: prioq_remove_match, arg: &arg); |
400 | } |
401 | |